Abstract
Apolipoprotein A1 (
APOA1
) is a potential biomarker because of its variable concentration in different types of cancers. The current study is the first of its kind to evaluate the association between the
APOA1
genotypes of −75 G/A and +83 C/T in tandem with the
APOA1
protein expression in urine samples to find out the risk and potential relationship for differentially expressed urinary proteins and
APOA1
genotypes. The study included 108 cases of bladder tumors and 150 healthy controls that were frequency matched to cases with respect to age, sex, and smoking status. Genotyping was performed using PCR-RFLP and the urinary expression of the
APOA1
protein was done using ELISA. Bladder tumor cases were significantly associated with the
APOA1
−75 AA genotype (
p
< 0.05), while the
APOA1
+83 C/T heterozygotes showed an association with cases (
p
< 0.05). The overall distribution of the different haplotypes showed a marked difference between the cases and controls in GT when compared with the wild type GC (
p
< 0.03). Bladder tumor cases that carried the variant genotype
APOA1
−75AA were found more (70.0%) with a higher expression (≥20 ng/mL)of the
APOA1
urinary protein and differed significantly against wild type GG (
p
= 0.03). Again, in low grade bladder tumors, urinary
APOA1
protein was exhibited significantly more (52.4% vs. 15.4% high grade) with a higher expression (≥20 ng), while high grade tumor cases (84.6% vs. 47.5% low grade) showed a lower
APOA1
expression (<20 ng/mL) (O.R = 6.08,
p
= 0.002). A strong association was observed between
APOA1
−75G/A and risk for bladder tumor and its relation to urinary protein expression, which substantiates its possible role as a marker for the risk assessment of the disease and as a promising diagnostic marker for different grades of malignant bladder tumors.